This invention relates to molded solid electrolyte capacitors having internal safety fuzes, and more particularly to such a capacitor wherein a blown fuze remains open circuit.
It is known in the prior art to provide a solid electrolyte capacitor with a fuze embedded in the molded casing for the capacitor. One frequent problem with such prior art fuzed constructions is that thermal fuzes may function properly to provide an open circuit, and then the debris of the fuze and adjacent charred molding material may reestablish a conductive path so as to put the capacitor back in the circuit.
The use of an exothermically alloyable fuze in a solid electrolyte capacitor has been taught by Shirn and Maher in U.S. Pat. No. 4,107,762 to overcome most of the problems associated with the thermally fuzed constructions. However the expense of exothermic fuzes, and the considerable care that is demanded in attaching such fuzes without igniting them, mediate against their use except for costly circuitry.
Various efforts in the prior art to provide a solid electrolyte capacitor with a fuze that does not reunite after being blown have included encasing the fuze in a material that does not char. Other efforts have involved tailoring leadframes so as to function as fuzable links and/or the use of blow-out plugs in molded casings so as to permit escape of fuze debris from the casings.
It is an object of this invention to provide a molded solid electrolyte capacitor with a fuze construction wherein blowing of the fuze results in a permanent open circuit. Another object is to provide such a fuzed capacitor that does not suffer damage to the molded package upon the fuze being blown. Another object is the provision of a simplified construction that is accommodated within a conventional molded casing without imposing a need to enlarge the mold.